2 Copyright (C) 2012-2021 Carl Hetherington <cth@carlh.net>
4 This file is part of DCP-o-matic.
6 DCP-o-matic is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 DCP-o-matic is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with DCP-o-matic. If not, see <http://www.gnu.org/licenses/>.
22 #ifndef DCPOMATIC_SIGNAL_MANAGER_H
23 #define DCPOMATIC_SIGNAL_MANAGER_H
26 #include "exception_store.h"
27 #include <boost/asio.hpp>
28 #include <boost/thread.hpp>
34 /** A class to allow signals to be emitted from non-UI threads and handled
37 class SignalManager : public ExceptionStore
40 /** Create a SignalManager. Must be called from the UI thread */
44 _ui_thread = boost::this_thread::get_id ();
47 virtual ~SignalManager () {}
49 SignalManager (Signaller const&) = delete;
50 SignalManager& operator= (Signaller const&) = delete;
52 /* Do something next time the UI is idle */
54 void when_idle (T f) {
58 /** Call this in the UI when it is idle.
59 * @return Number of idle handlers that were executed.
62 /* This executes one of the functors that has been post()ed to _service */
63 return _service.poll_one ();
66 /** This should wake the UI and make it call ui_idle() */
67 virtual void wake_ui () {
68 /* This is only a sensible implementation when there is no GUI */
73 /** Emit a signal from any thread whose handlers will be called in the UI
74 * thread. Use something like:
76 * ui_signaller->emit (boost::bind (boost::ref (SomeSignal), parameter));
80 if (boost::this_thread::get_id() == _ui_thread) {
81 /* already in the UI thread */
88 /* non-UI thread; post to the service and wake up the UI */
94 friend class Signaller;
96 /** A io_service which is used as the conduit for messages */
97 boost::asio::io_service _service;
98 /** Object required to keep io_service from stopping when it has nothing to do */
99 boost::asio::io_service::work _work;
100 /** The UI thread's ID */
101 boost::thread::id _ui_thread;
105 extern SignalManager* signal_manager;